SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f323cdf3a9dfaaee66ef326dade600825bc1fab4f85c000e97357dc4cd1132e' 
  AND token = '7YOPMSVLpJXM34A9tAf9bC/MRNas6IO6vGITBz8lJeU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}